Ensuring the quality of nanostructures by managing the formation of the por on the surface of semiconductors

Abstract

A general procedure is devised to control the process of formation of porous layers on semiconductor surfaces by the method of electrochemical etching. When controlling the process of pore formation on the surface of crystal, it is necessary to consider: conditions of pore formation, requirements that are put forward to quality of the obtained nanostructures, and mechanisms that underlie the process of pore formation. It is shown that the built scheme could be used for different cases of the synthesis of nanostructured semiconductors. We investigated the processes that underlie pore formation and define morphological properties of nanostructures. A thermodynamic analysis of processes at the boundary of contact «semiconductor – electrolyte» was performed. We examined a relative drop in potential in the Helmholtz layer, which is an important characteristic of the process of pore formation on the surface of crystal. Main morphological criteria are selected of quality of porous nanostructures for their application in solar batteries. These include diameter and depth of the pore, a degree of porosity of the surface of a nanostructured crystal. Taking into account these criteria, we received porous spaces on the surface of semiconductors A3V5 that could be used for solar cells. We determined the value of boundary voltage of the early pore formation for semiconductors of group A3V5 during etching in the electrolyte HF:C2H5OН:H2O=1:2:1 for 15 min. It was established that at chosen conditions of etching. the largest capacity to pore formation is displayed by crystals of indium phosphide. The results obtained demonstrate that at the same conditions of etching semiconductors possess different ability to form pores.